ABSTRACT Mitigation of climate change is a challenge to science and society. Here, we establish a... more ABSTRACT Mitigation of climate change is a challenge to science and society. Here, we establish a methodology, applicable in multi-disciplinary optimisation (MDO) during aircraft pre-design, allowing a minimisation of the aircraft’s potential climate impact. In this first step we consider supersonic aircraft flying at a cruise altitude between 45kfeet (~13·5km, 150hPa) and 67kfeet (~20·5km, 50hPa). The methodology is based on climate functions, which give a relationship between 4 parameters representing an aircraft/engine configuration and an expected impact on global mean near surface temperature as an indicator for the impact on climate via changes in the greenhouse gases carbon dioxide, water vapour, ozone and methane. These input parameters are cruise altitude pressure, fuel consumption, fuel flow and Mach number. The climate functions for water vapour and carbon dioxide are independent from the chosen engine, whereas the climate functions for ozone and methane depend on engine parameters describing the nitrogen oxide emissions. Ten engine configurations are taken into account, which were considered in the framework of the EU-project HISAC. An analysis of the reliability of the climate functions with respect to the simplified climatechemistry model AirClim and a detailed analysis of the climate functions is given.
The transport sector emits a wide variety of gases and aerosols, with distinctly different charac... more The transport sector emits a wide variety of gases and aerosols, with distinctly different characteristics which influence climate directly and indirectly via chemical and physical processes. Tools that allow these emissions to be placed on some kind of common scale in terms of their impact on climate have a number of possible uses such as: in agreements and emission trading schemes; when considering potential trade-offs between changes in emissions resulting from technological or operational developments; and/or for comparing the impact of different environmental impacts of transport activities.
Bei der Anwendung von globalen Klima-Chemiemodellen ist es von Bedeutung, dass der Rechenaufwand ... more Bei der Anwendung von globalen Klima-Chemiemodellen ist es von Bedeutung, dass der Rechenaufwand möglichst wenig mit der Zahl der zu transportierenden Spezies ansteigt und numerische Diffusion, die zu einem unphysikalischen Abbau von Spurenstoffgradienten führt, weitestgehend ausgeschaltet wird. Lagrangesche Verfahren erfüllen diese Anforderungen im Grundsatz wesentlich besser als rein Eulersche Verfahren. Auf der Lagrangeschen Beschreibung von Stömungen basierende numerische Verfahren haben gegenüber Eulerschen Verfahren den Vorteil, dass sie numerisch nicht diffusiv sind und die Verfolgung vieler unterschiedlicher sich durchmischender chemischer Substanzen und Spurenstoffe erlauben. Atmosphärenmodelle, die schon Lagrangesche Transportschemata beinhalten, sind derzeit noch Zwitter, wie zum Beispiel das Klima-Chemiemodell EMAC/ATTILA (EMAC: ECHAM5/MESSy Atmospheric Chemistry Model, ATTILA: Atmospheric Tracer Transport in a Lagrangian Model). Sie verwenden zwar einen Lagrangeschen Me...
Although the Montreal Protocol now controls the production and emission of ozone depleting substa... more Although the Montreal Protocol now controls the production and emission of ozone depleting substances, the timing of ozone recovery is unclear. There are many other factors affecting the ozone layer, in particular climate change is expected to modify the speed of re-creation of the ozone layer. Therefore, long-term observations are needed to monitor the further evolution of the stratospheric ozone layer. Measurements from satellite instruments provide global coverage and are supplementary to selective ground-based observations. The combination of data derived from different space-borne instruments is needed to produce homogeneous and consistent long-term data records. They are required for robust investigations including trend analysis. For the first time global total ozone columns from three European satellite sensors GOME (ERS-2), SCIAMACHY (ENVISAT), and GOME-2 (METOP-A) are combined and added up to a continuous time series starting in June 1995. On the one hand it is important t...
The Brewer-Dobson circulation (BDC) and tropical upwelling in the lower stratosphere are predicte... more The Brewer-Dobson circulation (BDC) and tropical upwelling in the lower stratosphere are predicted to increase with increasing greenhouse gas (GHG) concentrations by most climate models and chemistry-climate models (CCMs). This change in the meridional circulation is likely to alter the transport of trace gases, and in particular ozone. In addition, ozone is affected by other processes such as changes in stratospheric temperatures that act to change the reaction rates of ozone-relevant chemistry. These climate-change related modifications of the ozone amount and distribution are superimposed on the depletion and recovery of the ozone layer due to stratospheric halogen loading. To assess the recovery of ozone correctly, it is important to understand the processes that affect ozone in a changing climate. In this study, multiple transient numerical simulations and complementary sensitivity studies with the E39CA CCM are used to disentangle the direct effect of changes in GHG concentrat...
Atmospheric Chemistry and Physics Discussions, 2008
... A detailed description of the RETRO data set can be found in RETRO (2007, report available vi... more ... A detailed description of the RETRO data set can be found in RETRO (2007, report available via http://retro.enes.org/pub reports.shtml ... we will concen-5 trate on consequent advancements in interactions between planetary waves and the mean flow in terms of Eliassen-Palm (EP ...
ABSTRACT Methane is a long-lived greenhouse gas playing an important role in global climate chang... more ABSTRACT Methane is a long-lived greenhouse gas playing an important role in global climate change. Since preindustrial times atmospheric CH4 concentrations have more than doubled. The global CH4 budget is determined by the balance between surface emissions and different sink processes. Model projections of future atmospheric CH4 concentrations are complicated by uncertainties not only in the strength of individual CH4 sources, but also by uncertainties in other trace species affecting the major CH4 loss reaction.
The assessment model for ultraviolet radiation and risk "AMOUR" is applied to output fr... more The assessment model for ultraviolet radiation and risk "AMOUR" is applied to output from two chemistry-climate models (CCMs). Results from the UK Chemistry and Aerosols CCM are used to quantify the worldwide skin cancer risk avoided by the Montreal Protocol and its amendments: by the year 2030, two million cases of skin cancer have been prevented yearly, which is 14% fewer skin cancer cases per year. In the "World Avoided," excess skin cancer incidence will continue to grow dramatically after 2030. Results from the CCM E39C-A are used to estimate skin cancer risk that had already been inevitably committed once ozone depletion was recognized: excess incidence will peak mid 21st century and then recover or even super-recover at the end of the century. When compared with a "No Depletion" scenario, with ozone undepleted and cloud characteristics as in the 1960s throughout, excess incidence (extra yearly cases skin cancer per million people) of the "Fu...
Journal of Geophysical Research: Atmospheres, 2014
ABSTRACT [1] We have diagnosed the lifetimes of long-lived source gases emitted at the surface an... more ABSTRACT [1] We have diagnosed the lifetimes of long-lived source gases emitted at the surface and removed in the stratosphere using six three-dimensional chemistry-climate models (CCMs) and a two-dimensional model. The models all used the same standard photochemical data. We investigate the effect of different definitions of lifetimes, including running the models with both mixing ratio (MBC) and flux (FBC) boundary conditions. Within the same model, the lifetimes diagnosed by different methods agree very well. Using FBCs versus MBCs leads to a different tracer burden as the implied lifetime contained in the MBC value does not necessarily match a model's own calculated lifetime. In general, there are much larger differences in the lifetimes calculated by different models, the main causes of which are variations in the modelled rates of ascent and horizontal mixing in the tropical mid-lower stratosphere. The model runs have been used to compute instantaneous and steady-state lifetimes. For chlorofluorocarbons (CFCs) their atmospheric distribution was far from steady state in their growth phase through to the 1980s and the diagnosed instantaneous lifetime is accordingly much longer. Following the cessation of emissions, the resulting decay of CFCs is much closer to steady-state. For 2100 conditions the model circulation speeds generally increase, but a thicker ozone layer due to recovery and climate change reduces photolysis rates. These effects compensate so the net impact on modelled lifetimes is small. For future assessments of stratospheric ozone use of FBCs would allow a consistent balance between rate of CFC removal and model circulation rate.
ABSTRACT We present version 3.0 of the chemistry-climate model (CCM) SOCOL. The new model version... more ABSTRACT We present version 3.0 of the chemistry-climate model (CCM) SOCOL. The new model version is now based on the 5th generation of the general circulation model MA-ECHAM, which states a substantial progress compared to previous model versions. One main new feature is that the chemical species are transported by the operational flux-based advection scheme of ECHAM5 instead of a Semi-Lagrangian scheme. Therefore unphysical mass fixer corrections, which had to be applied in the former model versions to enable global mass conservation, can now be avoided. However, as a consequence of the time-dependent pressure coordinates in the sigma-layer system, it is still necessary to apply a family based correction scheme for species of the nitrogen, chlorine and bromine group. By means of these changes, SOCOL version 3.0 simulates physically realistic distributions of the chlorine and bromine containing species. Furthermore, total ozone shows a much more pronounced seasonal variability than in former model versions, which is close to observations, and the timing of the simulated ozone hole is improved.
ABSTRACT Mitigation of climate change is a challenge to science and society. Here, we establish a... more ABSTRACT Mitigation of climate change is a challenge to science and society. Here, we establish a methodology, applicable in multi-disciplinary optimisation (MDO) during aircraft pre-design, allowing a minimisation of the aircraft’s potential climate impact. In this first step we consider supersonic aircraft flying at a cruise altitude between 45kfeet (~13·5km, 150hPa) and 67kfeet (~20·5km, 50hPa). The methodology is based on climate functions, which give a relationship between 4 parameters representing an aircraft/engine configuration and an expected impact on global mean near surface temperature as an indicator for the impact on climate via changes in the greenhouse gases carbon dioxide, water vapour, ozone and methane. These input parameters are cruise altitude pressure, fuel consumption, fuel flow and Mach number. The climate functions for water vapour and carbon dioxide are independent from the chosen engine, whereas the climate functions for ozone and methane depend on engine parameters describing the nitrogen oxide emissions. Ten engine configurations are taken into account, which were considered in the framework of the EU-project HISAC. An analysis of the reliability of the climate functions with respect to the simplified climatechemistry model AirClim and a detailed analysis of the climate functions is given.
The transport sector emits a wide variety of gases and aerosols, with distinctly different charac... more The transport sector emits a wide variety of gases and aerosols, with distinctly different characteristics which influence climate directly and indirectly via chemical and physical processes. Tools that allow these emissions to be placed on some kind of common scale in terms of their impact on climate have a number of possible uses such as: in agreements and emission trading schemes; when considering potential trade-offs between changes in emissions resulting from technological or operational developments; and/or for comparing the impact of different environmental impacts of transport activities.
Bei der Anwendung von globalen Klima-Chemiemodellen ist es von Bedeutung, dass der Rechenaufwand ... more Bei der Anwendung von globalen Klima-Chemiemodellen ist es von Bedeutung, dass der Rechenaufwand möglichst wenig mit der Zahl der zu transportierenden Spezies ansteigt und numerische Diffusion, die zu einem unphysikalischen Abbau von Spurenstoffgradienten führt, weitestgehend ausgeschaltet wird. Lagrangesche Verfahren erfüllen diese Anforderungen im Grundsatz wesentlich besser als rein Eulersche Verfahren. Auf der Lagrangeschen Beschreibung von Stömungen basierende numerische Verfahren haben gegenüber Eulerschen Verfahren den Vorteil, dass sie numerisch nicht diffusiv sind und die Verfolgung vieler unterschiedlicher sich durchmischender chemischer Substanzen und Spurenstoffe erlauben. Atmosphärenmodelle, die schon Lagrangesche Transportschemata beinhalten, sind derzeit noch Zwitter, wie zum Beispiel das Klima-Chemiemodell EMAC/ATTILA (EMAC: ECHAM5/MESSy Atmospheric Chemistry Model, ATTILA: Atmospheric Tracer Transport in a Lagrangian Model). Sie verwenden zwar einen Lagrangeschen Me...
Although the Montreal Protocol now controls the production and emission of ozone depleting substa... more Although the Montreal Protocol now controls the production and emission of ozone depleting substances, the timing of ozone recovery is unclear. There are many other factors affecting the ozone layer, in particular climate change is expected to modify the speed of re-creation of the ozone layer. Therefore, long-term observations are needed to monitor the further evolution of the stratospheric ozone layer. Measurements from satellite instruments provide global coverage and are supplementary to selective ground-based observations. The combination of data derived from different space-borne instruments is needed to produce homogeneous and consistent long-term data records. They are required for robust investigations including trend analysis. For the first time global total ozone columns from three European satellite sensors GOME (ERS-2), SCIAMACHY (ENVISAT), and GOME-2 (METOP-A) are combined and added up to a continuous time series starting in June 1995. On the one hand it is important t...
The Brewer-Dobson circulation (BDC) and tropical upwelling in the lower stratosphere are predicte... more The Brewer-Dobson circulation (BDC) and tropical upwelling in the lower stratosphere are predicted to increase with increasing greenhouse gas (GHG) concentrations by most climate models and chemistry-climate models (CCMs). This change in the meridional circulation is likely to alter the transport of trace gases, and in particular ozone. In addition, ozone is affected by other processes such as changes in stratospheric temperatures that act to change the reaction rates of ozone-relevant chemistry. These climate-change related modifications of the ozone amount and distribution are superimposed on the depletion and recovery of the ozone layer due to stratospheric halogen loading. To assess the recovery of ozone correctly, it is important to understand the processes that affect ozone in a changing climate. In this study, multiple transient numerical simulations and complementary sensitivity studies with the E39CA CCM are used to disentangle the direct effect of changes in GHG concentrat...
Atmospheric Chemistry and Physics Discussions, 2008
... A detailed description of the RETRO data set can be found in RETRO (2007, report available vi... more ... A detailed description of the RETRO data set can be found in RETRO (2007, report available via http://retro.enes.org/pub reports.shtml ... we will concen-5 trate on consequent advancements in interactions between planetary waves and the mean flow in terms of Eliassen-Palm (EP ...
ABSTRACT Methane is a long-lived greenhouse gas playing an important role in global climate chang... more ABSTRACT Methane is a long-lived greenhouse gas playing an important role in global climate change. Since preindustrial times atmospheric CH4 concentrations have more than doubled. The global CH4 budget is determined by the balance between surface emissions and different sink processes. Model projections of future atmospheric CH4 concentrations are complicated by uncertainties not only in the strength of individual CH4 sources, but also by uncertainties in other trace species affecting the major CH4 loss reaction.
The assessment model for ultraviolet radiation and risk "AMOUR" is applied to output fr... more The assessment model for ultraviolet radiation and risk "AMOUR" is applied to output from two chemistry-climate models (CCMs). Results from the UK Chemistry and Aerosols CCM are used to quantify the worldwide skin cancer risk avoided by the Montreal Protocol and its amendments: by the year 2030, two million cases of skin cancer have been prevented yearly, which is 14% fewer skin cancer cases per year. In the "World Avoided," excess skin cancer incidence will continue to grow dramatically after 2030. Results from the CCM E39C-A are used to estimate skin cancer risk that had already been inevitably committed once ozone depletion was recognized: excess incidence will peak mid 21st century and then recover or even super-recover at the end of the century. When compared with a "No Depletion" scenario, with ozone undepleted and cloud characteristics as in the 1960s throughout, excess incidence (extra yearly cases skin cancer per million people) of the "Fu...
Journal of Geophysical Research: Atmospheres, 2014
ABSTRACT [1] We have diagnosed the lifetimes of long-lived source gases emitted at the surface an... more ABSTRACT [1] We have diagnosed the lifetimes of long-lived source gases emitted at the surface and removed in the stratosphere using six three-dimensional chemistry-climate models (CCMs) and a two-dimensional model. The models all used the same standard photochemical data. We investigate the effect of different definitions of lifetimes, including running the models with both mixing ratio (MBC) and flux (FBC) boundary conditions. Within the same model, the lifetimes diagnosed by different methods agree very well. Using FBCs versus MBCs leads to a different tracer burden as the implied lifetime contained in the MBC value does not necessarily match a model's own calculated lifetime. In general, there are much larger differences in the lifetimes calculated by different models, the main causes of which are variations in the modelled rates of ascent and horizontal mixing in the tropical mid-lower stratosphere. The model runs have been used to compute instantaneous and steady-state lifetimes. For chlorofluorocarbons (CFCs) their atmospheric distribution was far from steady state in their growth phase through to the 1980s and the diagnosed instantaneous lifetime is accordingly much longer. Following the cessation of emissions, the resulting decay of CFCs is much closer to steady-state. For 2100 conditions the model circulation speeds generally increase, but a thicker ozone layer due to recovery and climate change reduces photolysis rates. These effects compensate so the net impact on modelled lifetimes is small. For future assessments of stratospheric ozone use of FBCs would allow a consistent balance between rate of CFC removal and model circulation rate.
ABSTRACT We present version 3.0 of the chemistry-climate model (CCM) SOCOL. The new model version... more ABSTRACT We present version 3.0 of the chemistry-climate model (CCM) SOCOL. The new model version is now based on the 5th generation of the general circulation model MA-ECHAM, which states a substantial progress compared to previous model versions. One main new feature is that the chemical species are transported by the operational flux-based advection scheme of ECHAM5 instead of a Semi-Lagrangian scheme. Therefore unphysical mass fixer corrections, which had to be applied in the former model versions to enable global mass conservation, can now be avoided. However, as a consequence of the time-dependent pressure coordinates in the sigma-layer system, it is still necessary to apply a family based correction scheme for species of the nitrogen, chlorine and bromine group. By means of these changes, SOCOL version 3.0 simulates physically realistic distributions of the chlorine and bromine containing species. Furthermore, total ozone shows a much more pronounced seasonal variability than in former model versions, which is close to observations, and the timing of the simulated ozone hole is improved.
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Papers by Andrea Stenke